Daylight fluorescent pigments and process for preparing them

ABSTRACT

NEW DAYLIGHT FLUORESCENT PIGMENTS WHICH CONTAIN AN ORGANIC FLUORESCENT DYESTUFF AND AS RESIN A CONDENSATION RESIN CONSISTING OF COPOLYMERIZATES OF (METH)-ACRYLATES CONTAINING GROUPS CAPABLE OF BEING CROSS-LINKED AND VINYL COMPOUNDS CAPABLE OF BEING COPOLYMERIZED, WHICH COPOLYMERIZATES ARE CROSS-LINKED WITH UNPLASTICIZED, ALCOHOLMODIFIED UREA- OR AMINOTRIAZINE FORMALDEHYDE RESINS AND A PROCESS FOR THEIR PREPARATION WHICH COMPRISES INCORPORATING THE ORGANIC FLUORESCENT DYESTUFF INTO THE CONDENSATION RESIN. THESE DAYLIGHT FLUORESCENT PIGMENTS MAY BE EMPLOYED FOR PREPAARING FLUORESCENT PAINTS, FOR EXAMPLE AIRDRYING LACQUERS ON THE BASIS OF ALKYL RESIN OR PHYSICALLY DRYING LACQUERS ON THE BASIS OF ACRYLIC RESINS, AS WELL AS FOR PREPARING FLUORESCENT PRINTING INKS SUCH AS INKS FOR SCREEN PRINTING, INTAGLIO PRINTING, BOOK PRINTING AND OFFSETLITHO PRINTING: DUE TO THEIR HIGH RESISTANCE TO HEAT, THEY ARE ARTICULARLY SUITABLE FOR FLUORESCENT DYEING OF PLASTICS AND ENAMELS.

articularly suitable U iwd St tes 3795628 DAYLIGHT FLUOR ESC ENT PIGMENTS'AND PROCESS FOR PREPARING THEM Siegfried Noetzel, Mainz, Germany, assignor to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Bruning, Frankfort am Main, Germany No Drawing. Filed Nov. 9, 1971, Ser. No. 197,151 Claims priority, application Germany, Nov. 11, 1970,

' P 20 55 449.8 Int. Cl. C091: N02 US. Cl. 252-301.2 R

ABSTRACT OF'THE DIscLosiJRn New daylight fluorescent pigments which contain; an

1 organic fluorescent dyestutf and as resin a condensation resin consisting of copolymerizates of (methyacrylates containing groups capable of being cross-linked and vinyl compounds capable of being copolymerized, which copolymerizates are cross-linked with unplasticized, alcoholmodified ureaor aminotriazine formaldehyde resins and.

aprocess for their preparation which comprises incorporating the organic fluorescent-dyestufi into the condensation resin. These daylight fluorescent pigments may be employed for preparing fluorescent paints, for exampleairdrying lacquers on the basis of alkyd resin orphy'sical ly e drying lacquerson the basis of acrylic resins, as-well as for preparing fluorescent printing inks such as nks for screen printing, intaglio printing, book printing and offsetlitho printing. Due to their high resistance to-heat,'they are enamels.

The present invention relates to new daylight fluorescent pigments which contain an organic fluorescent dyestutf zates of (meth)-acrylates containing groupscapable" of being cross-linked and vinyl compounds capable of being copolymerized, which copolymerizates are cross linked with unplasticized, alcohol-modified urea-or -'aminotrifor fluorescent dyeing of plastics and Y and'as resin a condensation resin consisting of copolymeriazine formaldehyde resins. The invention also relates a process for preparing thedaylight fluorescent pigments comprising incorporating the organic fluorescentidyestutf into the condensation resin.

The definition of (meth)-acrylates containinggrbups capable of being cross-linked includes compounds of the series of the (meth)-acrylates which contain as reactive groups one or several hydroxyl, carboxyl, methylolor methylol ether groups, such as (meth)-acrylic*acid fi-hydroxy-alkyl ester, (meth)-acrylic acid, N-hydroxymethyl- 1 (meth)-acryl amide, N-methoxy-methyl-, N-pr opoxy'methyland N-butoxy-methyl-(meth)-acryl amide. A's vinyl compounds which may becopolymerized"with'-' these be considered for example (meth)-acryla'tes without reactive groups, as for'example (nieth)-acrylic facidjalkyland aryl-esters or other vinyl compounds such-as styrene, 5 methylstyreue, acryl-nitrile, vinyl chloride and vinylace- (meth)-acrylates containing reactive groups,-there"may The copolymerizates' oi (meth)-acrylates containing groups capable of being cross-linked and of the vinyl com pounds are prepared in accordance with known methods, for example by solution polymerization in solvents such I as ketones, esters, aromatic hydro carbons and alcohols with free-radical initiating catalysts such as dibenzoyljper oxide, dicumyl peroxide or a'zoisobutyronitrile. The use of mixtures of n-butanol and 'xylolenesfassolvents is Spreferred. There may be reacted mixtures of ditferentlmethy acrylates carrying reactive groupsas well as mixtures of 3,795,628 Patented Mar. 5, 1974 reactive groups incorporated into the copolymerizate ranges between 10 and 60% by weight, calculated on the sum total of all monomers to be copolymerized.

As resins for cross-linking, urea and aminotriazineformaldehyde condensates are used, as for example the unplasticized, alcohol-modified resins known from US.

- patent specification No. 2,498,592 and British patent specification No. 734,181, which are formed by condensation *of urea 01' aminotriazines with paraformaldehyde in alco- 10 "above all hols 'at -120" C. Examples for aminotriazines are :the 2,4-diamino-1,3,-5-triazine, the 2,4-diamino-6-methyl-1,3,5-triazine, the 2,4-diamino-6-(3-hydroxybutyl)-1,3,5-triazine,

the 2,4-diamino-6-heptyl-1,3,5-triazine, the 2,4-diamino-6-phenyl-1,3,5-triazine,

"the 2,4-diamino-6-benzyl-1,3,5-triazine,

the"2,4,6-triamino-1,3,5-triazine (melamine),

the 2,4-diamino-6-(fi-cyanoethyl)-l,3,5-triazine, and

the 2,4diamino-6-( cyanovalero)-1,3,5-triazine and'theirmixtures; 1 J j For preparing the condensation resins according to th invention, the solutionsof the copolymerizates are mixed "at room temperature with the resins for cross-linking dissolved in alcohol, and cured at C. C. if desired in vacu'o', the solvents being eliminated. As solvents for copolymerization there are preferably considered lower aliphatic alcohols or their mixtures with xylenes, the ratio being 1:9 to 9:1 parts by volume. The solutions of the copolymerizates and of the resins for cross-linking have concentrations between about 40 and 60 percent by weight. The cross-linking of the reactive (meth)-acrylate copolymc'rs with the resins for cross-linking is effected under the influenceor catalysts, such as phosphoric acid or citric acid or under the influence of the (meth)-acrylic acid which may be incorporated into the polymer (internal catalyst); 1

The amount of the resin for cross-linking added depends on the'type of the resin and on the required degree of hardness and brittleness of the final resin formed. The ratio of the copolymerizate to the cross-linking resin may generally vary from 80 to 20 until 20 to 80 parts by j weight.

It-ispossible to add to the mixture of copolymerizate 30 percent by weight, calculated on the total amount of copolymerizate and resin for cross-linking. The condensation resins thus-obtained are characterized by a good transparency and purity and by a sufificient resistance to organic solvents, oxygen and to moisture. They are also more resistant to heat and to light than the resins known from US. patent specifications Nos. 2,498,592,

12,8 9,954, 2,938,873, 3,116,256 and 3,412,036, British I patentspecifications Nos. 734,181, 748,484, 792,616 and 11,048,983fand from German patent specification No. 961,- 65.

inventionparticularly suitable for being used in daylight fluorescent pigments. Daylight fluorescent pigments consist of a colorless finely ground base resin, into which a 5 75. ['I'hese properties render the resins according to the "fluor escent'dyestuif has been incorporated. Such daylight several vinyl compounds capable of being copolymerized. The amount of the monomer or their mixture containing pigmentsfj'are employed more and more in the lacquer,

"printing ink and plastics industry as well as in the field of textilesand for the coating of paper.

The fluorescent. dyestufis may be incorp ate into the, was con inued in the same w y as indicated above. Cured base resins by severalrnethods. Ihus,..they..may -be.diswe productsnofi an=intense greenyellowfluorescencewere obsolved or dispersed either in the mixture of the solutions tained, which decomposedat temperatures between 300 of copolymerizate and cross-linking resin to be condensed and 330 C. For converting the cured products into a dayor in the individual resin solutions, and then the resinmay 5 light fluorescent pigment, they were finely ground in a ball be cured. The dyestuifs may also be used in ,such a; forrn mill. 4 parts of the da'y-lightfluorescent pigment thus obas to be chemically bound to the individual resins; tair'idwe'r-inixed for one hour ina'po'rcelain ball mill on ,The cured product thus-obtained is, then converted into the roller with 96" parts ofn-polystyrene,which was pula finely divided form by dry or wetgrinding in-.a; ballror "yerized-"ifi'ahainmer mill. Then the mixture was molded perl mill. Grinding is expediently carried out in the'pres- "tea mates at 240C. The fpressed plate had anintense ence of water. The particle: size of" the. daylight pi mcnt, green ry' llow fluorescence. 1 Y which may vary within wide .lim its, depends to a large eX- -'.Iristead oflthe, above-mentioned melamine-formaldetent on the application field desired.- ,Thus, the average hyde-resin solution, there mayalso be used resin solutions particle size of the daylight fluorescent pigment generally ii for cross-linking, prepared from 55lnpartsof benzoguanaranges between about 5 and 301.1,, if it shall be-used for mine, 360 parts of paraformaldehyde and 9l0-parts' of preparing printing inks for silk screen printing or for pren-butanol or from lgo parts of acetoguanamine, 120parts paring lacquers, and between about 0.1 'and-5-,u ,if-printir"1g of paraiormaldehyde and 250 parts ofn-butanol. inks shall be prepared. As fluorescentdyestuffs there' are If in the above example the copolyme'rizate resin is reconsidered organic compounds which are fluorescent by u *placed by a sulfonamide resin,'prepared by'melting condaylight in dissolved or solid, crystallineform, as z-for densat'iOn, at'140-150 C., of 1710 parts of p-toluene sulexaniple fluorescent dyestulfs of the rhodamine', sulfo "fonamide'and 600 parts of paraformaldehyde, cured prodrhodamine or naphtalimide series; Moreover, the dye- 7 ucts were obtained which changed their color already at stuffs described in French patent specifications Nos. aboiit 200-' C. and decomposed at 220-250 C. 1,590,506, 1,444,489, 1,488,113 and 1,470,793 ma -be p used Y 5 EXAMPLE 2 The concentration of the dyestufl in the resin depends A g r la' ifi l ti i n-butanollp-xylene was above all on the type of the resin, on the dyestuff usedand i 'p 'd i th same manner a in -Example 1 from 28 on the desired application o ay p e parts of acrylic acid, 178parts of "methyl methacrylate, dyestuff concentration generally ranges ee a ou 0- i 1271'p'a'rts of hydroxyethyl methacrylate, 268 parts of nand 10 P t y weight- The y g t p prefer- 30 biityl rhethacrylate and .12 parts of dibenzoyl peroxide.

ably contains the dyestuff in a concentration,wh'ichproh content of lid o ted to about 45 vides the best possible brilliancy, the tinctorial strength of If 70, 60 01" 0 parts y Weight of this acl'ylatc resin the Pflllihlct y with this dyeshlff being 8 solution were mixed with 30, 40 or 60 parts by Weight of The daylight fluorescent pigments according to e jthe melamine-f0rmaldehyde-resin solution described in Exvehtioh y be p y Preparing fluorescent Paints, ample '1 and if the mixtures were cured during 17 hours at example aiHh'yhlg lahqhels Oh the hasls'hf alkyd 150 C. in vacuo (300 mm. of Hg), transparent solid resin Physically 'y lacquers 011 the i -fi 'y products were obtained which could be finely ground in resins, as well as for preparing fluorescentprinting ir'iks h laglb'mill. They decomposed at 310-340? C, v

such as inks for Screen P g, inlagho p in i h 'For preparing a daylight fluorescent pigment, the above- PliIltihg and Offset-limo P Due 10 their h' h 40 described acrylate-resin solution was mixed with themelance to heal, y are Particularly 'fi l QS l 'amineformaldehyde-resin solution according to Example y g of Plastics, Which e u ally P ,betWEel1 .:1,.which contained 2% of,benzothioxanthene-3,4-dicarand and 0f enamels which a ostoved above boxylie acid hydrazide, the ratios being 70:30,- 60:40 and C. 1 40:60 andcuredat 150 C. in vacuo (300mm. Hg) during The following amples illustrate the invention, :17 hours. After grinding in known manner, the cured prod- EXAMPLE 1 ucts3resulted1-in daylight fluoroescent pigments of aninj-tensep,green yellowfluorescence, which decomposed at A mixture of 28 parts of acryl c acid, 178 parts,-.-of e C. I H

methyl methacrylate, 127 parts of hydroxy-ethyll fi h Instead 0f: the =10-methoxy-benzoxanthene-3,4-dicar- 90 Parts of nbutylmethacrylater 178921115 of lboxylic.acidhydrazide, the following fluorescent dyestufis during two hours to a boiling mixture of ,240 parts by styrene and 7 Parts of dibenzoyl 'P d? 'QJ maybe used-(the fluorescent shades are indicated): benz- 1oxanthene-3,4-dicarboxylic acid amide (green), benzox- Weight of h'blltahol and 4901321115 y Weight of prl l tanthene 3,4 dicarboxylic acid-N-3'-su1fonamido-pheny1 Then the mixture was heatfid for another o 119 431 imide-;(green),.benzothioxanthene 3,4-dicarboxylic acid After adding 4 Parts of dibehzoyl f l d ii stem'ylioimide (greenish yellow), benzothioxanthene-3,4- mixture was refluxed for another two hours and after l .dim,flwxylic'acid hydrazide (grgenishpyenow), adding 1 part of dibenzoyl peroxide for still anothertwo .1 8 h l ztfigdi h l phenyl imide,(green) b.

hours. The content of solids amounts to abouf,,45% and l4 thi dib (b d f) h {orange yellow), B has, thus, eached the the r i lama fthe-daylight fluorescent pigment obtained ac- P p h Solution of Fesih cording to the aboveexamplewere mixedfor 5 minutes 1 Parts ofmelamme n Parts O pe m l e .at- 1001-10. "with 90 parts of a pulverized polyvinyl chlowere refluxed for 3 hours in 122413Elrts f hl h hA -dhh -ride', ,which: contained 3% --of an organictinstabilizcr-and .solids of 45.5%

ball mill. The products were decomposed at, 30

colorless resin Solution W Obtained ha l g'a o trento 1% of oxystearine acid on a double roller mixer. There-- 7 r v sultingcoat -was stripped, oil and compression molded tors If 70, 5O 40 Parts of the above 'y fi h h-fi lh o ,1 minutes atfll'iO C. The pressed sheet had an intense greenare mixed with 30, 40 or 60 parts of the above resinsolull ,fl tion for cross-linking and the individualmixtures were f EXAMPLE 3 cured for 17 hours at 150 C. and 300 mm of I-Ig, andthe p solvent was eliminated, pure, brittle cured products wefre According tothe process of Example 1, an acrylate resin obtained, which could be ground to a fine pew r in. ,a 'so:lutioii-'in n butanol/ p xylene was. prepared. from. 28 30:30. fipa'rtsofuacrylicf acid,l178 parts of methyl 'methac'r'ylate, For preparing a daylight fluorescent pig" ,,,4 %I 'of T127 parts of hydroxyethyl methacrylaite, 90 part's of .n- 10-methoxy-benzoxanthene-3,4-dicarboxylicj; a Qhydrabutyl.,methacrylate, 178 partsof e-methylsty'r'ene and 12 zide were added as fluorescent dyestutf vvhen ftl ie 'fresin eams of dibenzdyl peroxidejhavinga content of. solids'of solution for cross-linking was prepared, andlthe reaption about4 5%,

If 70, 60 or 40 parts by weight of this acrylate resin solution were mixed with 30, 40 or 60 parts by weight of the melamine-formaldehyde resin solution according to Example 1 and the mixtures cured at 150 C. in vacuo (300 mm. of Hg) for 17 hours, transparent brittle solid products were obtained, which decomposed at 300320 C.

For preparing a daylight fluorescent pigment, a melamineformaldehyde resin solution was used in the above example, which contained 2.2% of rhodamine B in a dissolved form.

The cured products obtained weer finely ground in a ball mill. Thus, a red fluorescent daylight pigment was obtained which decomposed at 300-320 C.

For preparing an enamel, 20 parts of the daylight fluorescent pigment obtained according to the above example were ground for 20 minutes on the paint-shaker together with 45 parts of xylene, 25 parts of a 60% solution of a short-oil, non-drying alkyl resin from 37% of oil (triglyceride) and 40% of phthalic acid anhydride in xylene and with parts of a 50% solution of a non-plasticized melamine resin in alcohols and aromatic hydrocarbons in the presence of quartzite perls (2-3 mm. in a 200 ml. plastic beaker. The lacquer obtained was sprayed on white-coated test plates (30 x 30 cm.) and stoved for minutes at 160 C. The resulting lacquer had an intense red fluorescence.

EXAMPLE 4 According to the process of Example 1, an acrylate resin solution in 240 parts of n-butanol and 490 parts of p-xylene was prepared by mixed polymerization of 28 parts of acrylic acid, 178 parts of methyl-methacrylate, 127 parts of hydroxyethyl methacrylate, 268 parts of n-butyl methacrylate and 30 parts of methacrylamide with 12 parts of dibenzoyl peroxide and then reacted for 30 minutes at 100 C. with 9.8 parts of paraformadelhyde.

70, 60 or 40 parts by weight of this acrylate resin solution were mixed with 30, 40 or 60 parts by weight of the melamineformaldehyde resin solution of Example 1 and cured at 150 C. in vacuo (300 mm. Hg) for 17 hours. The resulting cured products decomposed at 300-320 C.

If in the above example a melamine-formaldehyde-resin solution was usd which contained 4% of IO-methoxy-benzoxanthene-3,4 dicarboxylic acid hydrazide in dissolved form, cured products were obtained which yielded, after 6 being ground in a ball mill, yellow-green fluorescent daylight pigments.

I claim:

1. A daylight fluorescent pigment composition comprising an organic fluorescent dyestuff and a cross-linked condensation resin of (a) 20% to 80% by weight of a copolymerizate having groups capable of being cross-linked that is a copolymerization product of about 10% to about by weight of methacrylic acid, hydroxy lower alkyl methacrylate, N-hydroxy lower alkyl methacrylamide, N- lower alkoxy lower alkyl methacrylamide, acrylic acid, hydroxy lower alkyl acrylate, N-hydroxy lower alkyl acrylamide or N-lowe'r alkoxy lower alkyl acrylamide, and of about 90% to about 40% by Weight of methacrylic acid alkyl ester, methacrylic acid aryl ester, styrene, methyl styrene, acrylonitrile, vinyl chloride or vinyl acetate, and (b) to 20% by weight of an unplasticized alcoholmodified condensate of urea or 2,4-diamino-, 2,4-diamino- 6-methyl-, 2,4-diamino-6-(3-hydroxy-butyl)-, 2,4-diamino- 6-heptyl-, 2,4-diamino-6-phenyl-, 2,4-diamino-6-benzyl-, 2,4,6-triamino-, 2,4-diamino-6-(fi-cyanoethyl)- or 2,4-diamino-6-(omega-cyanovalero)-1,3,5-triazine with paraformaldehyde.

2. A daylight fluorescent pigment according to claim 1 wherein the cross-linked condensation resin contains additionally 5% to 30% of the reaction product of Bisphenol A and epichlorhydrin which contains at least two epoxide groups.

References Cited UNITED STATES PATENTS 2,938,873 5/1960 Kazenas 252-3013 R 3,222,418 12/1965 Murdock 260856 3,382,294 5/1968 Christenson et a1. 260856 3,412,036 11/1968 McIntosh 260856 3,532,768 10/1970 Dalibor et al. 260-850 3,532,769 10/1970 Dalibor et al. 260--850 3,532,770 10/ 1970 Dalibor et al. 260-850 DANIEL E. WYMAN, Primary Examiner A. P. DEMERS, Assistant Examiner US. Cl. X.R. 

